KR20020063178A - Liquid gas exchanger - Google Patents

Abstract

Heat exchangers are used to transfer heat from water to liquid nitrogen. When heat is transferred from water to liquid nitrogen, the temperature of the water is lowered and the liquid nitrogen is converted to nitrogen gas. Cooled water and nitrogen gas are used in one or more semiconductor manufacturing devices in semiconductor manufacturing processes. This lowers the total power consumption of the semiconductor manufacturing process because the water is cooled by passing water through the liquid nitrogen to convert the liquid nitrogen into nitrogen gas used in the semiconductor manufacturing process.

Description

Liquid Gas Heat Exchanger {LIQUID GAS EXCHANGER}

1 is a diagram illustrating a general design of a semiconductor manufacturing apparatus (clean room). The clean room includes zones for film growth, precipitation, photolithography, etching, ion implantation and photo-resist stripping. In clean rooms, the processing equipment may include chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems, injectors, furnaces, rapid thermal processing (RTP) systems, etchers, plasma CVD systems, steppers, and SEMs. (scanning electron microscopes). Generally, some of the heat generated by the processing device (eg, about one third) is transferred to the coolant. Coolers are used to produce chilled water and these coolers were used in 1996 by C.Y. Chang and S.M. It accounts for 18% of the total power consumption of a typical clean room according to the "ULSI technology" published by Sze.

The processing apparatus also uses nitrogen gas, such as carrier gas, reactive gas, dopant, purge gas, diluent gas, etc. in various semiconductor manufacturing processes. Nitrogen can be used to operate with air in semiconductor manufacturing devices. In general, nitrogen is stored in the tank in liquid state to maintain space. To convert liquid nitrogen to nitrogen gas, liquid nitrogen can travel through a pie with fins (eg, heat exchangers) exposed to the atmosphere to absorb heat at ambient conditions. Still other gases used in semiconductor manufacturing processes include oxygen and argon.

One problem with the prior art is that a separate cooler is provided for cooling the coolant. This takes up space and consumes power, increasing the cost of wafer fabrication. In addition, since the liquefied gas is heated to gas, power is consumed to increase the cost of the manufacturing process.

FIELD OF THE INVENTION The present invention relates to methods and systems for producing coolants and gases for use in semiconductor manufacturing devices, and more particularly to liquid nitrogen in water for lowering the temperature of water and converting liquid nitrogen into nitrogen gas for use in semiconductor manufacturing processes. To the use of a heat exchanger to transfer heat to the furnace.

1 shows a design of a conventional clean room;

2 and 6 show block diagrams of a cooling system according to the invention;

3A and 3B are schematic views of the heat exchanger of FIGS. 2 and 6 in accordance with an embodiment of the present invention;

4, 5 and 7 are flowcharts of a method for operating the cooling system of FIGS. 2 and 6; And

8 and 9 show block diagrams of an air conditioning unit that can be used with the cooling system of FIGS. 2 and 6.

According to one aspect of the invention, a cooling system includes a heat exchanger for supplying coolant and gas to one or more device portions used in semiconductor manufacturing processes. The heat exchanger is combined with a coolant (eg water) source and a liquid gas source (eg liquid nitrogen) to transfer heat from the coolant to the liquid gas, whereby the coolant is cooled and the liquid gas is vaporized. The heat exchanger is combined with one or more units of the semiconductor manufacturing apparatus to supply coolant and gas. According to an embodiment, the heat exchanger may supply coolant and gas to the same or another device.

According to another aspect of the invention, a method of lowering the temperature of a coolant (eg, water) comprises supplying a coolant from a coolant source to a heat exchanger, transferring liquid gas (eg, liquid nitrogen) from a liquid gas source to a heat exchanger Supplying, and supplying a coolant from the heat exchanger to the semiconductor manufacturing apparatus. The method also includes supplying a liquid gas in a gas state from a heat exchanger to the same semiconductor manufacturing device or to another semiconductor manufacturing device.

The present invention provides a reduction in semiconductor manufacturing costs. The coolant used in the semiconductor manufacturing process is cooled with little use of the cooler. Instead, the coolant is cooled using a liquid gas that is converted to a gaseous state for use in semiconductor manufacturing processes. Thus, energy consumption by the cooler is minimized and semiconductor manufacturing costs are also reduced.

2 illustrates a cooling system 100 according to one aspect of the present invention. The valve 102 selectively couples the liquid gas source 104 to the inlet 106 of the heat exchanger 108 or the inlet 110 of the heat exchanger 112. For example, valve 102 is a conventional valve produced by Omega Engineering, Inc. of Stamford, Connecticut. Liquid gas source 104 is a conventional tank that stores liquid nitrogen and stores liquid gas.

The inlet 106 is coupled with a pipe 114 through the chamber 113 formed by the heat exchanger 108. The pipe 114 is coupled with the outlet 118 of the heat exchanger 108. The valve 120 optionally couples the outlet 118 of the heat exchanger 108 or the outlet 122 of the heat exchanger 112 with the gas supply pipe 124. Valve 120 is a valve of the same type as valve 102. Pipe 124 is coupled with conventional semiconductor manufacturing apparatus 126A to supply nitrogen gas. Apparatus 126A may include chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems, injectors, furnaces, rapid thermal processing (RTP) systems, etchers, plasma CVD systems, steppers, SEMs ( scanning electron microscopes) and air conditioning units.

Heat exchanger 112 includes a pipe 128 having an outer surface attached to fin 130. Heat exchanger 112 is exposed to the atmosphere to transfer heat from ambient air to liquid nitrogen passing through heat exchanger 112.

Valve 132 optionally couples coolant source 134 with inlet 136 of heat exchanger 108 or inlet 138 of conventional cooler 140. Valve 132 is a valve of the same type as valve 102. The coolant stored in the coolant source 134 is, for example, water supplied from a city water line or deionized water supplied from a deionized water source. The coolant source 134 may also include a water purification device to remove impurities that affect the heat transfer capability of the water or affect precipitation or corrosion formed inside the coolant passages.

Although liquid nitrogen and water are described in conjunction with the system 100 of FIG. 2, the system 100 may be used to heat or cool the coolant and / or another liquid gas needed in the semiconductor fabrication process. For example, another suitable liquid gas may include liquid oxygen and another suitable coolant including liquid argon and glycols.

Inlet 136 is coupled with heat exchanger 108 such that water flows into chamber 113 formed by heat exchanger 108. In the chamber 113, on the other hand, water is deprived of heat from the nitrogen that contacts the pipe 114 and travels in the pipe 114. Water cooled by the liquid nitrogen is discharged from the heat exchanger 108 through the outlet 142.

The cooler 140 is a conventional cooler used to lower the temperature of the water. Water moves from the inlet 138 into the cooler 140 and is discharged through the outlet 146. Valve 144 optionally couples outlet 142 of heat exchanger 108 or outlet 146 of cooler 140 with a coolant supply pipe. Pipe 148 is coupled to apparatus 126A for supplying cooling water. In one embodiment, the apparatus 126A may be comprised of an air conditioning unit that utilizes coolant (or other suitable air conditioning coolant) to produce cooled air used in the semiconductor manufacturing apparatus. Although the pipes 124 and 128 are described as supplying coolant and nitrogen gas to the same device 126A, the pipes 124 and 128 are each one or more identical or different semiconductor devices (e.g., devices 126B and 126C). ) Can be supplied with cooling water or nitrogen gas.

The control unit 150 controls the valves 102, 120, 132 and 144. The control unit 150 is, for example, a conventional temperature control unit produced by Omega Engineering Co., Ltd. In normal operation, control unit 150 has (1) valve 102 coupling source 104 and inlet 106 and (2) valve 120 coupling outlet 118 and pipe 124. And (3) valve 132 couples source 134 and inlet 136, and (4) valve 144 engages outlet 142 and pipe 148. In the chamber 113 of the heat exchanger 108, water is in contact with the pipe 114 and heat is transferred from the water to the pipe 114 from the pipe 114 to nitrogen. Nitrogen is changed from liquid to gas before exiting the heat exchanger 108 through the outlet 118. The water is deprived of heat in the pipe 114 and cooled to a certain temperature before exiting the heat exchanger 108 through the outlet 142. Nitrogen gas and cooling water are housed in apparatus 126A for use in semiconductor manufacturing processes.

If the temperature of the water discharged from the heat exchanger 108 is too high, the control unit 150 bypasses the heat exchanger 108 and uses the cooler 140. If the water discharged from the heat exchanger 108 is too cold, the control unit may convert liquid nitrogen from the heat exchanger 108 to the heat exchanger 112 until the water discharged from the heat exchanger 108 reaches a predetermined temperature. Can be. This operation is described later with reference to FIG. 4.

3A and 3B show top, side and front views of heat exchanger 108. As shown in FIG. 3A, chamber 103 has a width W, a length L and a height H. As shown in FIG. Those skilled in the art will appreciate that the actual sizes of W, L and H are determined by the needs of cooling water and / or nitrogen gas in the clean room.

Pipe 114 includes a combination of junction 154-i, straight pipe 156-j, junction 158-k, straight pipe 160-1, and U-shaped pipe 162-m. . Where i, j, k, l, m are integers representing the number of pipes 154, 156, 158, 160 and 162, and their values vary with the number of levels of pipe 114. Referring to the top view (top of FIG. 3A), the pipe 114 begins at the junction 154-1, which couples the inlet 106 to the pipe 156-1. Next junction 158-1 joins pipe 156-1 and pipe 160-1. Another junction 158-2 joins pipe 160-1 and pipe 162-1. Pipe 162-1 is used to rotate pipe 114 180 degrees in the plane (first plane) where the pipe described above is located.

Next junction 158-3 joins pipe 162-1 and straight pipe 160-2. The junction 158-4 couples the straight pipe 160-2 and the pipe 162-2. Pipe 162-2 is used to rotate pipe 114 180 degrees in a plane aligned with pipe 160-2 and perpendicular to the first plane. Referring to the side view (bottom of FIG. 3A), the joining of the pipes described above is repeated for additional levels of pipe 114. At the final level, the junction 154-2 joins the pipe 156-2 (the end of the pipe 114) and the outlet 118.

As will be appreciated by those of ordinary skill in the art, pipe 114 may be made of one pipe that is bent to form another combination of pipes or the structure shown in FIG. 3A. The use of a single pipe can reduce leakage while periodically heating or cooling inside the heat exchanger 108.

Referring to the front view (FIG. 3B), the outer surface of the pipe 114 is attached with a fin 164 to increase heat transfer between the water filling the chamber 103 and nitrogen in the pipe 114. For example, eight fins 164 are arranged at equal intervals around the outer surface of the pipe 114. The front view also shows that adjacent pipes 160-1 on the same level are arranged a distance "S" away from the center. Adjacent pipes 160-1 on adjacent levels are arranged at a distance "S" from the center thereof. As will be appreciated by those of ordinary skill in the art, the actual size of the "S", the size and length of the pipe is determined by the needs of the coolant and / or nitrogen gas of the clean room. Also, while pipes 160-1 are arranged at a distance " S ", pipes 160-1 can be disposed at other distances.

4 shows a method 200 of a system 100 for maintaining the temperature of water discharged from a heat exchanger 108 between a temperature range T1 and T2, where T1 is greater than T2. The method 200 begins with step "202". In step 202, the operator sets the control unit 150 to the predetermined temperatures T1 and T2. At step 204, control unit 150 fills chamber 113 with water and allows liquid nitrogen to flow through pipe 114. This allows the control unit 150 to (1) allow the valve 102 to couple the nitrogen source 104 and the inlet 106 so that (2) the valve 120 connects the outlet 118 and the pipe 124. (3) the valve 132 to engage the water source 134 and the inlet 136 so that the water is not discharged from the chamber 113 through the outlet 142 to the closed position. Hold the valve 144.

(Once the chamber 113 is filled with water) In step 206, the control unit 150 determines whether the temperature of the water is too high, for example, to determine if the temperature of the water near the outlet 142 is greater than the temperature T1. The temperature sensor 152 is used to find out. If the temperature of the water near the outlet 142 is too high, the flow proceeds from step 206 to step 208. Otherwise, the flow proceeds from step 206 to step 210.

The temperature of the water near the outlet 142 is sometimes changed depending on the amount of water and pipe 114 contacting in the chamber 113. The person skilled in the art does not change the temperature of the water near the outlet 142, and the water in the chamber 113 is equally in contact with the pipe when the water moves down the chamber 113 toward the outlet 142. Can be understood as being distributed. In addition, a person of ordinary skill in the art has a high tolerance (e.g., ± 10 to 20 ° C) for cooling the temperature of water (e.g., 30 deg. C), and water has an equal temperature. It can be seen that it is a good thermal conductor distributed well. Alternatively, a mechanical mixer may be arranged to mix the water in chamber 113 to keep the temperature of the water passing through chamber 13 constant.

In step 208, the control unit 150 uses the cooler 140 to bypass the heat exchanger 108 and cool the water to a predetermined temperature. In this way, the control unit 150 has (1) a valve 102 coupling the nitrogen source 104 and the inlet 106, and (2) a valve 120 coupling the outlet 118 and the pipe 124. And (3) valve 132 couples water source 134 and inlet 138, and (4) valve 144 couples outlet 146 and device 126A. Heat exchanger 108 may be utilized to supply nitrogen gas to apparatus 126A. Upon transitioning from step 206 to step 208, the method 200 is repeated until the temperature of the water near the outlet 142 is less than the temperature of T1.

In step 210, the control unit 150 utilizes a heat exchanger 108 to supply cooling water and / or nitrogen gas to the apparatus 126A. In this way, the control unit 150 has (1) a valve 102 coupling the nitrogen source 104 and the inlet 106, and (2) a valve 120 coupling the outlet 118 and the pipe 124. And (3) valve 132 couples water source 132 and inlet 136, and (4) valve 144 couples outlet 142 and device 126A. In step "208", step "210" is performed.

In step "212", the control unit 150 may determine if the temperature of the water near the outlet 142 is less than T2, for example, to determine if the temperature of the water is too low (e.g., if the water is cooled The temperature sensor 152 is used. If the temperature of the water discharged from the heat exchanger 108 is too low, the flow goes from step 212 to step 214. Otherwise, the flow proceeds to step "216" from step "212".

In step 214, the control unit 150 uses the heat exchanger 112 to bypass the heat exchanger 108 and convert liquid nitrogen into nitrogen gas, whereby water in the heat exchanger 108 is It becomes higher than temperature T2. As a result, the control unit 150 has (1) a valve 102 coupling the nitrogen source 104 and the inlet 110, and (2) a valve 120 coupling the outlet 122 and the pipe 124. And (3) valve 132 couples water source 134 and inlet 136, and (4) valve 144 couples outlet 142 and device 126A. Heat exchanger 108 may be used to allow cooling water to be supplied to device 126A. Proceeding from step 212 to step 214, the method 200 repeats until the temperature of the water near the outlet 142 is greater than the T2 temperature.

In step 216, control unit 150 utilizes heat exchanger 108 to supply cooling water and / or nitrogen gas to device 126A. In this way, the control unit 150 has a valve 102 connecting the nitrogen source 104 and the inlet 106, (2) the valve 120 connects the outlet 118 and the pipe 124, ( 3) The valve 132 connects the water source 134 and the inlet 136, and (4) the valve 144 connects the outlet 142 and the device 126A. Upon transition from step "206" to step "216", the cycle of the steps described above is maintained to maintain the temperature of the water releasing the heat exchanger 108.

5 shows a method 500 of a system 100 for maintaining the temperature of water discharged from the heat exchanger 108 between the temperatures of T1 and T2, where T1 is greater than T2. The method 500 is identical to the method 200 except that step "208" is replaced by step "508" and step "214" is replaced by step "514".

Step 508 is the same as step 208 except that the control unit 150 sets the valve 132 to supply water to both the heat exchanger 108 and the cooler 140. In one embodiment, the valve 132 is set to supply water simultaneously to two points. In step 508, the heat exchanger 108 is used to couple with the cooler 140 when the temperature of the water discharged from the heat exchanger 108 is too high. Turning a portion of the water away from the heat exchanger 108 may reduce the amount of water deprived of heat with liquid nitrogen, thereby reducing the temperature of the water discharged to the heat exchanger 108.

Step 514 is the same as step 214 except that the control unit 150 sets the valve 102 to supply liquid nitrogen to both the heat exchangers 108 and 112. In one embodiment, the valve 102 is set to supply water to two points. In step 514, when the temperature of the water discharged from the heat exchanger 108 is too low, the heat exchanger 108 is used in conjunction with the heat exchanger 112. Turning a portion of the liquid nitrogen away from the heat exchanger 108 may reduce the amount of liquid nitrogen absorbing heat from the water in the chamber 113, thereby increasing the temperature of the water discharged from the heat exchanger 108. You can.

6 illustrates a cooling system 600 in accordance with another aspect of the present invention. System 600 includes a valve 602 having a lower flow of valve 132 and an upper flow of inlet 136, and a valve 604 having a lower flow of valve 102 and an upper flow of inlet 106. Same as system 100 except as noted. The control unit 150 is a means for controlling the temperature of the water discharged from the heat exchanger 108 (described in method 700) to control the flow rate of water and nitrogen in the heat exchanger 108. 602 and 604). The cooler 140, heat exchanger 112 and pipes and valves associated therewith are selected as one embodiment of the system, where valves 602 and 604 control the temperature of the water discharged from the heat exchanger 108. Means of unit 150.

FIG. 7 shows a method 700 of a system 600 for maintaining the temperature of water discharged from the heat exchanger 108 between T1 and T2. The method 700 includes a step "208" replaced by step "708", a step "214" replaced by a step "714", and the control unit during normal operation of the heat exchanger (step "210" and step "216"). Same as method 200 except that 150 opens valves 602 and 604 to a first position (eg, 50% open).

Step 708 is step 210 except that the control unit 150 increases the nitrogen flow rate of the heat exchanger 108 and reduces the water flow rate instead of bypassing the cooler 140 and the heat exchanger 108. Is the same as " By reducing the flow rate of water, a small amount of water can be deprived of heat to liquid nitrogen, thereby reducing the temperature of the water. By increasing the nitrogen flow rate, a large amount of liquid nitrogen can absorb heat from the water in the chamber 113, thereby reducing the temperature of the water. To reduce the flow rate of water, the control unit 150 closes the valve 602 to the second position (25% open). To increase the nitrogen flow rate, the control unit 150 opens the valve 604 to a third position (eg, 75% open).

Step 714 is except that the control unit 150 increases the nitrogen flow rate of the heat exchanger 108 and / or decreases the water flow rate instead of bypassing the heat exchanger 108 and the heat exchanger 112. Is the same as step "216". Increasing the flow rate of the water allows a large amount of water to lose heat to the liquid nitrogen, thereby increasing the temperature of the water. By reducing the nitrogen flow rate, a small amount of liquid nitrogen removes heat from the water in the chamber 113. Absorption, thereby increasing the temperature of the water discharged from the heat exchanger. To increase the flow rate of the water, the control unit 150 opens the valve 602 to a third position (eg, 75% open). To reduce the flow rate of nitrogen, the control unit 150 closes the valve 604 to the second position (25% open).

One use of the coolant discharged from the heat exchanger 108 is to cool the refrigerant (coolant) of the air conditioning unit that keeps the temperature within the allowable limits of many semiconductor manufacturing devices located in the semiconductor manufacturing device. 8 shows one embodiment of an air conditioning system 800 used in conjunction with systems 100 and 600. The air conditioning system 800 includes a heat exchanger (coolant bed) 808 used to cool the refrigerant of the air conditioning unit 850. The refrigerant is released to the air conditioning unit and enters the chamber 813 of the coolant bed 808 through the inlet pipe 806. Inlet pipe 806 is coupled to one end of pipe 814 that moves within chamber 813. Another end of the pipe 814 is coupled with the outlet pipe 818 to return the refrigerant to the air conditioning unit 850. The coolant bed 808 and the pipe 814 have similar structures, such as, for example, the heat exchanger 108 and the pipe 114. The water cooled in the heat exchanger 108 enters the chamber 813 through the pipe 148 (which acts as the inlet of the heat exchanger 108) and exits the chamber 813 through the outlet pipe 842. do. In the chamber 813, the cooled water contacts the pipe 814 and cools the refrigerant.

In yet another embodiment, the heat exchanger 108 operates like a coolant bed. As shown in FIG. 9, the refrigerant enters the chamber 113 of the heat exchanger 108 through the pipe 806. Pipe 806 is coupled with one end of pipe 814 moving within chamber 113. Another end of the pipe 814 is coupled with the pipe 818 to return the refrigerant to the air conditioning unit 850.

Although the present invention has been described with reference to specific embodiments, the detailed description is only one example of the present invention and is not limited thereto. For example, another type of heat exchanger may be used in place of heat exchanger 108 depending on the actual application. In addition, if the capacity of the heat exchanger 108 is insufficient, the heat exchanger 108 may use the heat exchanger 112 and the cooler 140 simultaneously to produce the required amount of coolant and / or nitrogen gas. In addition, if the flow of liquid nitrogen or water is reduced in any of the above applications, conventional devices may be used in conjunction with systems 100 and 600 as required by semiconductor manufacturing devices. Various features of various applications and combinations of the embodiments can be varied within the scope of the invention as defined by the following claims.

Claims (38)

Source of liquid gas; Source of coolant; A first semiconductor manufacturing apparatus; And A first heat exchanger, The first heat exchanger includes a first inlet coupled to a source of coolant for supplying coolant to the first heat exchanger; A first outlet coupled to the first semiconductor manufacturing device, wherein the first heat exchanger supplies a coolant to the first semiconductor manufacturing device through the first outlet; A second inlet coupled with a source of liquid gas for supplying liquid gas to the first heat exchanger; And And a second outlet for supplying the liquid gas in a gas state used in a semiconductor manufacturing process. The method of claim 1, The coolant comprises water and glycol. The method of claim 1, Said liquid gas comprises liquid nitrogen, liquid oxygen and liquid argon. The method of claim 1, The second outlet is coupled to a first semiconductor manufacturing apparatus, and the first heat exchanger supplies a liquid gas in a gas state to the first semiconductor manufacturing apparatus through the second outlet. The method of claim 1, Further comprising a second semiconductor manufacturing device, The second outlet is coupled to a second semiconductor manufacturing device, and wherein the first heat exchanger supplies a liquid gas in a gas state to the second semiconductor manufacturing device through the second outlet. The method of claim 5, And a second heat exchanger having a third inlet and a third outlet coupled with the second semiconductor fabrication apparatus. The method of claim 6, And a first valve coupled with the second inlet, the source of liquid gas and the third inlet, wherein the first valve optionally flows liquid gas from a source of liquid gas to a second inlet or third inlet A system, characterized in that. The method of claim 6, And a first valve coupled with the second inlet, the source of liquid gas and the third inlet, the first valve flowing liquid gas from both the source of liquid nitrogen to the second inlet and the third inlet. System characterized in that. The method of claim 7, wherein And further comprising a second valve coupled to the second outlet, the third outlet, and the second semiconductor manufacturing device, wherein the second valve selectively selects a liquid gas and optionally a second semiconductor at the second outlet or the third outlet. A system characterized by flowing into a manufacturing apparatus. The method of claim 6, And the second heat exchanger further comprises a second pipe having a first end coupled with a third inlet and a second end coupled with a third outlet, the second pipe being exposed to ambient conditions. . The method of claim 6, Fourth inlet; And a cooler having a fifth outlet coupled with the first semiconductor manufacturing device. The method of claim 11, And a third valve coupled with the source of coolant, the first inlet and the fourth inlet, the third valve selectively flowing coolant from the source of coolant to the first inlet or the fourth inlet. System. The method of claim 11, And a third valve coupled with the source of coolant, the first inlet and the fourth inlet, wherein the third valve flows the coolant from the source of coolant to both the first inlet and the fourth inlet. System. The method of claim 11, And further comprising a fourth valve coupled to the first outlet, the fourth outlet, and the first semiconductor manufacturing device, wherein the fourth valve selectively transfers coolant from the first or fourth outlet to the first semiconductor manufacturing device. A system characterized in that the flow. The method of claim 14, Further comprising a temperature sensor positioned near the first outlet. The method of claim 15, And a control unit coupled to at least one of said temperature sensor, said first valve, said third valve, said fourth valve and said fifth valve. The method of claim 1, The first semiconductor manufacturing apparatus includes a chemical vapor deposition (CVD) system, a physical vapor deposition (PVD) system, an injector, a furnace, a rapid thermal processing (RTP) system, an etching machine, a plasma CVD system, a stepper, a scanning electron microscope (SEM) And an air conditioning unit. The method of claim 1, And a fifth valve coupled with the first inlet and the source of coolant, the fifth valve flowing coolant to the first inlet at a selected rate. The method of claim 18, And a sixth valve for coupling the second inlet with the source of liquid gas, the sixth valve flowing liquid gas to the second inlet at a selected rate. The method of claim 19, Further comprising a temperature sensor positioned at the first outlet. The method of claim 20, And a control unit coupled with at least one of said temperature sensor, said fifth valve and said sixth valve. The method of claim 1, The heat exchanger includes: a fifth inlet coupled to an air conditioning unit for supplying refrigerant to the first heat exchanger; And a fifth outlet for supplying coolant to the air conditioning unit. The method of claim 1, A fifth inlet coupled with an air conditioning unit for supplying refrigerant to a third heat exchanger; A fifth outlet, wherein the third outlet supplies coolant to the air conditioning unit; A sixth inlet coupled with the first outlet, wherein the first outlet supplies coolant to a third heat exchanger through the sixth inlet; And And a third heat exchanger having a sixth outlet for discharging said coolant from said third heat exchanger. Supplying coolant from the coolant source to the first heat exchanger; Supplying liquid gas from a liquid gas source to the heat exchanger, where the liquid gas is changed to a gas state and the coolant is cooled; Supplying a cooled coolant from the first heat exchanger to a first semiconductor manufacturing apparatus; And A method for conserving energy in semiconductor manufacturing comprising supplying a liquid gas used in a semiconductor manufacturing process in a gaseous state. The method of claim 24, If the cooled coolant supplied from the first heat exchanger to the first semiconductor manufacturing apparatus is higher than a predetermined temperature, Supplying coolant from said coolant source to a cooler; And Supplying a coolant from said cooler to a first semiconductor manufacturing device. The method of claim 24, Supplying the liquid gas in a gas state comprises conveying the liquid gas in a gas state to the first semiconductor manufacturing apparatus. The method of claim 24, Supplying the liquid gas in a gas state comprises conveying the liquid gas in a gas state to the second semiconductor manufacturing apparatus. The method of claim 27, If the coolant supplied from the heat exchanger to the first semiconductor manufacturing apparatus is lower than a predetermined temperature, Supplying liquid gas from the liquid gas source to a second heat exchanger; And Supplying a liquid gas in a gas state from the second heat exchanger to a second semiconductor manufacturing device. The method of claim 24, And said coolant comprises water and glycol. The method of claim 24, The liquid gas comprises liquid nitrogen, liquid oxygen and liquid argon. The method of claim 24, If the cooled coolant supplied from the first heat exchanger to the first semiconductor manufacturing apparatus is greater than a predetermined temperature, supplying coolant from the coolant source to the first heat exchanger and cooler. The method of claim 31, wherein Supplying a coolant from said cooler to said first semiconductor manufacturing device. The method of claim 24, Supplying the liquid gas from the liquid gas source to the first heat exchanger and the second heat exchanger if the cooler supplied from the heat exchanger to the first semiconductor manufacturing apparatus is lower than a predetermined temperature. . The method of claim 33, wherein Supplying a liquid gas in a gas state from the second heat exchanger to a second semiconductor manufacturing device. The method of claim 24, If the cooled coolant supplied from the first heat exchanger to the first semiconductor manufacturing apparatus is higher than a predetermined temperature, Reducing coolant flow rate from the coolant source to a first heat exchanger; Increasing liquid gas flow rate from the liquid gas source to a first heat exchanger; or Reducing coolant flow rate from said coolant source to a first heat exchanger and increasing liquid gas flow rate from said liquid gas source to a first heat exchanger. The method of claim 24, If the coolant supplied from the heat exchanger to the first semiconductor manufacturing apparatus is lower than a predetermined temperature, Reducing the liquid gas flow rate supplied from the liquid gas source to the first heat exchanger; Increasing the coolant flow rate from the coolant source to the first heat exchanger; or Reducing the liquid gas flow rate supplied from the liquid gas source to the first heat exchanger and increasing the coolant flow rate supplied from the coolant source to the first heat exchanger. The method of claim 24, Supplying a refrigerant from the air conditioning unit to the first heat exchanger, where the refrigerant is cooled; And Supplying a cooled refrigerant from said first heat exchanger to an air conditioning unit. The method of claim 24, Supplying a coolant cooled from the first heat exchanger to a third heat exchanger; Supplying a refrigerant from the air conditioning unit to the third heat exchanger, where the refrigerant is cooled; And Supplying a cooled refrigerant from said third heat exchanger to an air conditioning unit.